1. Field of the Invention
The present invention relates generally to connection-oriented communications networks, and more specifically to a signaling technique for establishing a virtual connection in a network such as asynchronous transfer mode (ATM) network.
2. Description of the Related Art
Studies on signaling protocols for ATM networks were undertaken by international bodies such as Working Party XI/6 of CCITT Study Group XI and ATM Forum, and proposals were made in the form of draft standards such as Draft Text for Q.93B, pages 1 to 14 and Signaling Specification Draft, pages 14 to 20, respectively.
While the proposals secure availability for many types of variable length signaling message and provide such flexibility that signal units can be inserted into any location of a message, a substantial amount of time will be taken to establish a virtual connection due to increased processing time and increased propagation delays. Specifically, each network node is required to examine the called party address contained in the signaling message to determine the link to the next hop. When the route extends to the desired called party address, the signaling is made on the basis of the called party subaddress contained in the message. As a result, the processing time taken by each node of the network increases, and the connection establishment time will be increased significantly with an increase in the number of network nodes.